Amid a state-sponsored campaign of ethnic cleansing against the Rohingya people, activists have urged luxury jewelers to stop sourcing gems from Myanmar, a major source of precious minerals.

An online petition calling on Cartier to cut ties with Myanmar, which produces about 90% of the world’s jade and rubies, has garnered nearly 77,000 signatures since it launched in early-December. According to the US Department of Commerce, the military government takes a significant portion of mining proceeds and owns large stakes in the mines.

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After Cartier announced it would stop sourcing gems from Myanmar on Dec. 8, the disinvestment campaign turned its attention to the jewelry brand Bulgari and the behavior of individual consumers.

“[Holiday] shoppers this year will want to consider their role in propping up the genocide of Rohingya people,” wrote activist Hannah Lownsbrough in a Guardian opinion piece. Lownsbrough directs the website SumOfUs, which hosts the petition.. “There is a long and shameful tradition of corporations being slow to disentangle themselves from genocidal regimes.”

Over the past few decades, disinvestment campaigns have raised awareness about injustices, convinced corporations to act responsibly, and pressured oppressive governments. In the late 1980s, disinvestment campaigns helped topple South Africa’s apartheid state and motivated companies to stop purchasing “blood diamonds” that fund conflicts in Africa — though some unscrupulous companies still manage to get these stones to market.

Read More: Myanmar Blocks Investigators as Reports of Mass Grave in Rakhine State Emerge

Since August, Myanmar’s government has backed an ethnic cleansing campaign against the Rohingya Muslim minority, disregarded reports of widespread rape and abuse, and compelled hundreds of thousands of Rohingya individuals to flee into neighboring Bangladesh. On Wednesday, Myanmar said it would block international inspectors from visiting the country amid reports of mass graves.

UNICEF reports that more than 320,000 Rohingya children have fled Myanmar and about 12,000 children arrive at refugee camps in Bangladesh each week since the wave of violence began this past summer.

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Read more: Timeline: How the Rohingya Crisis Unfolded in Myanmar

In her essay, Lownsbrough challenged Bulgari to uphold its own commitment to “conducting its business in a socially responsible manner.”

“We want all jewellery corporations to stop selling items containing gems mined, processed or traded by companies owned by the [Myanmar] army,” she wrote. “Bulgari, stop buying gems from a regime responsible for slaughtering thousands upon thousands of its own citizens.”